Method and apparatus for radar surveillance and detection of sea targets

In a system that detects relatively fast moving targets using a radar clutter map comprising a plurality of range-azimuth cells containing parameter data values indicative of time averaged echo returns for affecting alarm threshold levels at range-azimuth locations scanned by the radar system antenna, an apparatus for detecting relatively slow moving targets in a substantially homogeneous surveillance region comprising:

• a processor adapted to obtain from said radar clutter map a value corresponding to parameter data of a given cell under test (CUT), said processor including a logic unit that determines a second parameter data value using parameter data values of other cells from said plurality of range-azimuth cells from said radar clutter map;
• a comparator that compares the parameter data value of said CUT with said second parameter data value and generates a signal indicative of a target detection when said CUT parameter data value exceeds said second parameter data value by a given threshold corresponding to a target false alarm rate.